1. Field of the Invention
The present invention relates to a measuring apparatus for measuring light emitted from a specimen.
2. Description of the Related Art
As a measuring apparatus that analyzes statistical properties and molecular-level functions on a specific region in a specimen, for example, Japanese PCT National Publication No. 11-502608 discloses a method and apparatus that are based on a confocal optical microscope and obtain statistical properties such as the translational diffusion coefficients of fluorescent molecules, intermolecular interactions, and the like by applying laser light to a fluorescence-labeled specimen through the microscope objective lens, and analyzing fluorescence intensity fluctuations from fluorescent molecules in the specimen (performing fluorescence correlation spectroscopy).
As a description about a confocal optical microscope, for example, “Confocal Microscopy”, T. Wilson (ed.), Academic press (London) is available. As a description mainly concerning a biological specimen, for example, “Handbook of Biological confocal Microscopy”, J. B. Pawley (ed.), Plenum Press (New York) is available. With regard to a fluorescence correlation spectroscopy, there are available descriptions such as “Fluorescence correlation spectroscopy”, R. Rigler, E. S. Elson (eds.), Springer (Berlin) and Masataka Kinjo, “Protein, nucleic acid and enzyme”, (1999) Vol 44, No. 9, pp. 1431–1437.
According to fluorescence correlation spectroscopy, fluorescence-labeled protein or carrier particles are suspended in a solution within the field of view of a confocal scanning laser microscope, and an autocorrelation function is obtained by analyzing fluorescence intensity fluctuations based on the Brownian motion of the particles, thereby estimating the number, translational diffusion velocity, and the like of particles.
On the other hand, there is available confocal scanning laser microscope, which applies laser light to a fluorescence-labeled sample specimen by scanning the laser light, and generates a fluorescence microscope image of the specimen. A confocal scanning laser microscope is described in, for example, Jpn. Pat. Appln. KOKAI Publication No. 10-206742. There are also available descriptions made by Takahiro Oode et al. (“Optics”, Vol. 18, Vol. 8, pp. 392–398), by Satoshi Kawata (“Optics”, Vol. 18, Vol. 8, pp. 380–391), and the like.
According to U.S. Pat. No. 5,120,953, in a laser scanning confocal optical microscope, light from the laser source is guided to the optical fiber and to the microscope body, thereby irradiating a specimen surface with the light. A light signal from the specimen is guided to the optical fiber again through the microscope body and is received by the photodetector connected to the optical fiber. That is, the light source and photodetector are optically connected to the microscope body through the optical fiber. According to U.S. Pat. No. 5,161,053, light from the light source of a confocal optical microscope is guided to the microscope body through an optical fiber, and a light signal from a specimen is optically branched to be guided to another optical fiber so as to be received by the photodetector optically connected thereto.
Japanese PCT National Publication No. 2001-505997 discloses a unit that is directly connected to a microscope to perform FCS measurement. A light source input/output port and a light signal output port are installed in this unit. Signal light output from the output port is received by a photodetector to perform FCS measurement.
In addition, Japanese PCT National Publication No. 2003-524180 discloses a unit that is connected to a microscope to perform FCS measurement. A light source body is incorporated in this unit. Light exits from the unit and is guided to the microscope, thereby irradiating the specimen with the light. A light signal emitted from the specimen is received in the unit through the microscope, and FCS measurement is performed.